I have a similar deck, and here's some things I would suggest adding: Dimir Infiltrator/Drift of Phantasms/Dimir House Guard: These guys can all be discarded in order to get important cards to your game plan
Goblin Tutor Rarity: Uncommon TYPE: Instant SUBTYPE: - CMC: 1 Mana cost: USD: $2.40 EUR: 0.95 TIX: 0.00 EDHREC RANK: - Roll a six-sided die
The deck adds a number of acceleration spells including cards such as Cultivate, Kodama's Reach, Rampant Growth, as well as mana rocks such as Arcane Signet, Commander's Sphere, and Sol Ring to help you cast your spells far ahead of curve
The Walls of Ba Sing Se Speaking of high mana cost, colorless permanents that work well in a wide range of different decks, meet The Walls of Ba Sing Se, and yes they are tall, aren't they
Ragavan, Nimble Pilferer is already being hailed as one of the best 1-mana red creatures ever printed and its not hard grasp why